Method and apparatus for obtaining indicator cards from engines



Aug. 1s, 1931. G, D, ANGLE 1;819,143

METHOD AND APPARATUS FOR OB`TAINING INDICATOR CARDS FRC!! ENGINES originali Filed Feb. 19, 1920 INVEN TOR L .BY GE/voA/vqLf Patented Aug. 18, 1,931y

PATENT OFFICE f GLENN 'n ANGLE, or lcnvcrivivrr'rr,l onro METHOD ANDAPPARA'rusroR OBTAINING INnIcA'r-oncanns Enom ENGINES rgvinal application filled. February 19, 1920, Serial No. 359,815. Divided kand this application ed February 27, 1929.

`The present invention relates to a method for obtaining indicator cards from engines,

y or containers for velements under positive or negative pressure. v

kThe invention has for a purpose to provide amethod whereby the average constant or mean pressure ot varying pressures, or of any series otliuctuating pressures in any machiney or device in` whichthere is pressure, or'in which there are varying,cor fluctuating pressures, may be obtained.

A further object is to provide a method whereby the average or mean pressure or any cyclic series of pressures may be obtained.

A futher object is kto provide a process whereby thefaverage yor mean pressure or pressures of yany cyclic series of fluctuating pressures maybe recorded for any point in the cycle.l I' l c Anotherobject kis vto provide a method for,y accurately obtaining and recording the pressure within an enclosure.

Another object is lto provide a method for accurately recording the krpressures within the cylinder-,or cylinders of an engine at any point in the cycle thereof while the ,engine is running at any given speed. To thisnendit is contemplated to devise means whereby pressures at any selective point or pointson the cycle may beobtained irrespecltive `of and excluding all other points at that particular instant', or at those particular instants, respectively.

Various devices have been heretofore proposed with such purposes in view but they havebeen found to be generally at `fault in that thereis usually an error due to the inertia of reciprocating parts employed to show the variations in` pressures during thecycle, and in most-,instances therecords obtained .were etfectedby the inertia characteristics ,of the reciprocating parts and therefore did not give any correctpressures.

yTo overcome these disadvantages it is proposed to' employ an apparatus having no oscillatingxparts operating at engine speed, .thus avoiding anyjinertia forces to be overcomefand.thereby the indicator responsive means for any given cycle will not oscillate Ajandkwill register, a sharp line on any kre- Serial No. 343,139.

- The invention is shown by wayrof illusn i tration in the accompanying drawings of one embodiment of my invention, as applied to an internal combustion engine, wherein Figure 1 is a side elevational view thereof. Figure 2 is a central sectional view of the same. f

Figure 3 is a horizontal sectional View on line 3 3 of Figure 2.

Figure 4 is a similar view taken on line 1e-4; of Figure 2.

Referring to the construction in further detail and wherein like reference characters indicate corresponding parts inthe ditferent views shown, the apparatus consists of a portion 5 adapted to be suitably mounted and secured upon, or immediately adjacent, the engine whose cylinders are to be tested. Said yportion' provides a pressure chamber 6 and a passage-way 7 communicating therewith through a. screen or gauze protected port' 8 for establishing communication with theV cylinders of the engine by a suitablecpipe connected to the port 9. f

A piston 1() operates within the chamber 6 under the pressure generated in the en gine cylinder and against the several springs v11'and a pencil or other scribing device 12 .is secured to the `piston rod 13 for recording on the'indicator card 14 that is suitably attached by the spring clip or other device 15 on the rotatable head 16 as shown. y

c The rotatable' head 16 has a tubular part, sleeveor extension 17 journaled within the bearing and passage-way provided bythe bore 7 in part 5 and said sleeve is formed with a pair of relatively narrow ports 18 and 19 which are substantially.. out of direct diametral line with'one another and hfve constant communication with the annular chambers 2O and 21, that open into the intake and Fis,

ioo

discharge ports 9 and 8, respectively, (see Figures 3 and 4).

A hollow shaft 22 extends through the head and sleeve (16 and 17) and is connected at its lower end through mitre gearing 24, 23 to be rotatively driven by any suitable transmission such as cam shaft below, at or above cam shaft speed. At its upper end the shaft 22 may be temporarily, as by screw plug 26, or permanently closed in a gas-tight manner and is provided with a flange to afford security within the head 10. Suitable means may be provided to prevent up and down movement of the shaft 22 while in operation and the gear 24 is held on the shaft 22 by a nut 28. The passageway or chamber 29 communicates with ports 18, 19 through ports 30, 31, (see Figures 3 and 1) of the same size and thereby provides communication between the pressure chamber 0 and the pressures to be tested. The volume of the chamber 29 may be made small in comparison with the volume of chamber G whereas the indicator card will be calibrated to correct for other errors incidentto use of indicator mechanism generally, such as speed of operation. Each joint 7 is made practically gas-tight and is impreg nated with graphite to maintain a. seal as well as for lubrication.

For convenience we may consider kport 9 in closed communication with an engine cylinder, consequently any pressure in annular chamber 20 is substantially that in the engine cylinder. Should it be desired to obtain the pressure value at a point in the cycle the in dicator may be geared to the cam shaft to rotate at the proper speed (in the case of a four-cycle engine at halt-engine or cam shaft speed) so that one revolution of the sleeve 22 takes place during each cycle and the ports 18 and 30, 19 and 31, register once during each cycle. The head and sleeve 17 may be rotated by hand or otherwise to any position and will be retained in that position by means not shown or by friction to determine relatively to the cycle, any point at which the value of the pressure is desired. Thus it follows that at any one particular point in the cycle the pressure will be indicated.

To minimize uctuations of pressure in chambers 29 and 0 and consequently oscillations orP the scribing means, this mechanism has been devised whereby to cut oil or trap a gas or vapor under any instantaneous pres sure and transmit that pressure indirectly to the scribing mechanism. To this end also, the ports 1S and 19 are arranged in staggered relation, that is, they are not diametrically opposite one another across the sleeve 17 but are placed less than 180 degrees apart, as shown in Figure a.

In operation an instantaneous pressure will be set up in chamber 29 and that pressure will be the pressure in the engine cylinder at a point in the cycle dependent upon the re.a-

tion of the point of juxta-position of the ports 18, 30 with the cycle. As the sleeve 22 rotates the pressure will be trapped in chamber 29 until the port 31 registers with the port 19, whereupon the pressure is transmitted lto the chamber 6. Upon each successive registration of the ports 18, 30 and relatively later registration of ports 31, 19, at a particular point in the cycle, a mean pressure will -be gradually builtup inchamber for tliatpoint in the cycle, which pressure will be indicated on the graph with a minimum of `fluctuation or oscillation.

It will be seen that the indicator `has utility for measuring and testing the eflicieney of manifolds, intake or exhaust, by measuring the cyclic fluctuation of 4pressure of either the intake or exhaust.

It will be understood that it `is not intended to limit my invention by the particular embodiment as shown and described, except by the claims herein.

The present application is a `division of my former application tiled on the 19th day of February, 1920, Serial No. 359,815, and which has eventuated .in Patent No. 1,720,710, granted July 10, 1929.

I claim:

1. The method of .ascertaining the mean pressure of any cyclic series of pressures for any point in the cycle which comprises, trapping in a closed chamber an instantaneous pressure at that point, maintaining said pressure inert and out of communication Vwith the recording device until transferred and transferring said pressure to the pressure recording device.

2. The method of ascertaining the mean pressure of any cyclic series of pressures for any point in the cycle'which comprises, trapping an instantaneous pressure in a chamber, maintaining said pressure inert for a period, transferring said pressure to `a. second chamber, cutting ofi' the second chamber romthe first, repeating the above mentioned steps until a substantially lconstant pressure is obtained in the second chamber and noting the pressure.

3. The method of ascertaining the mean pressure of any series-of pressures which consists in trapping in a chamber independently and intermittently at selective intervals the instantaneous pressures at those selective intervals, transferring those pressures independently and intermittently to another substantially closed chamber to build up the pressures therein and recording the resultant pressure.

f1. rI'he method of ascertaining the average constant of fluctuating pressures which consists in trapping in a closed chamber, independently and intermittently in accordance with a characteristic of the fluctuations, a series of said pressures, intermittently and independently passing the aforementioned lpressures out ofsaid chamber subsequently and successively to their entrance therein and into a secondclosed chamber whereby to build up an average constant of said fluctuating pressure and indicating the resultant pressure. s

5. The method of ascertaining and indicat-y ing a fluid pressure which consists in trapping the fluidunder pressure in a closed cham- 1o ber, closing the chamber against communication with the uid under pressure, and thereafter opening the chamber for transferring said pressure to an indicating device.

6. The method of ascertaining and indieating cylinder pressure at any point in the s cycle of operation of an engine, comprising Strapping at the desired point of the cycle iuid at cylinder pressure in a chamber, closing the chamber against communication with the cylinder under pressure, and thereafter opening the chamber for transferring said pressure kto a pressure indicating device, said steps of trapping, closing and opening being repeated for each cycle of operations of the engine.

In testimony whereof I aiiX my signature.

kGLENN D. ANGLE. 

